1. Field of the Invention
The present invention relates to an improvement of a vehicle exhaust system support structure in which exhaust gas discharged from an engine of a vehicle such as an automobile is guided to a muffler, muffled, and then released to the outside air.
2. Description of the Related Art
Conventionally, in a vehicle such as an automobile, an exhaust pipe of an exhaust system connected to an engine generally extends rearward beneath a vehicle body, and a tail pipe at the downstream end thereof is exposed below a rear bumper. For example, Japanese Utility Model Registration Application Laid-open No. 61-146428 (FIG. 3) discloses an arrangement in which an exhaust pipe (tail pipe) of an exhaust system is passed beneath a rear panel (rear bumper) 1, and an exhaust outlet 4 thereof is exposed to the outside. However, there is a problem that this exposure of the tail pipe to the outside is undesirable from the viewpoint of improvement of the appearance of the vehicle.
Japanese Patent Application Laid-open No. 3-96434 (FIG. 7 and ‘Prior Art’ section) discloses an arrangement as technical means for solving the above problem, in which a finisher 10A connected to an end part of a tail pipe 4A is disposed in the interior of a rear bumper 5A, and (in order to prevent exhaust gas from being caught up in the interior of the rear bumper) an open end of the finisher 10A is extended to an opening 6A formed in the rear bumper 5A. However, as is described in the above patent publication (‘Problems to be Solved’ section), since this conventional arrangement does not employ a structure for damping vibration of the tail pipe 4A (finisher 10A), it is necessary to ensure that a gap δ1 between the opening 6A of the rear bumper 5A and the open end of the finisher 10A is large so that the open end of the finisher 10A does not interfere with the edge of the opening 6A as a result of the vibration of the tail pipe 4A. That is, although the finisher 10A is disposed within the rear bumper 5A in order to improve the appearance, the gap δ1 is noticeable, leading to a further problem that a sufficient improvement in the appearance cannot be obtained.
In order to solve the problem of the noticeable gap δ1, Japanese. Patent Application Laid-open No. 3-96434 (FIG. 1 to FIG. 6) discloses an arrangement in which, by fixing a rear end part of a tail pipe 4 to a floor panel 14 by means of stays 12 and 13, a finisher 10 is prevented from swinging and interfering with an edge of an opening 6A of a rear bumper 5 even when the gap δ1 is reduced as much as possible, thus giving an effect in improving the appearance, and vibration of the exhaust system transmitted from the engine side is absorbed by a flexible tube 7 disposed partway along the tail pipe 4.
Although the flexible tube generally has an advantage that its vibration absorbing properties are high, there is a disadvantage that the axial core of the upstream side exhaust pipe and the axial core of the downstream side exhaust pipe, which are connected via the flexible tube, might be displaced from each other during vibration absorption, thus reducing the effective passage area of these exhaust pipes to increase the exhaust resistance. In the arrangement disclosed in Japanese Patent Application Laid-open No. 3-96434 (FIG. 1 to FIG. 6), the flexible tube 7 disposed partway along the tail pipe 4 provides a further problem of an increase in the exhaust resistance.